The Reproductive Character And Regrowth Performance Of Old World Bluestem (Bothriochloa Ischaemum) Population In Shanxi Rangelands

The studies were carried on the regrowth yield, quantitative characters of vegetative propagation and sexual reproduction of Old World bluestem (Bothriochloa ischaemum) population in Shanxi rangelands. The follow is the chief results of this research:1. There is an obvious regularity between quantitative characters of vegetative propagation of the Old World bluestem population. The plant number, aboveground biomass, and number of sexual plant of the tuft are increased exponentially with its increasing sizes. The weight of sexual plant of the tuft is increased with its increasing sizes power-functionally. There were all significant positive linear correlation between aboveground biomass and the plant number of the tuft, and number of sexual plant and weight of sexual plant. The ratio between numbers of sexual and agamous plant of the tuft is changed conically with mean height of tuft.2.There were all significant positive linear correlation between the height of the tillers and the length of spike, the number of seeds per spike, the weight of vegetative organs of the tillers, the weight of reproductive organs of the tillers, the weight of total tillers, the weight of thou sand seeds, and all significant negative linear correlation between the height of the tillers and the ratio of reproductive growth, reproductive allocation â…  , reproductive allocation â…¡, the set percentage by quantitative analysis. The ecological plasticity and regular change of quantitative characters of the tillers contained the strategies of individual on the growth and the reproduction.3.The effects of different first clipping dates and stubble heights of three clippings on Old World bluestem population indicated that the total dry matter yield was highest (740.31 DM kg/hm2) clipping firstly at the middle ten days in July and 4cm stubble, and treatment clipping firstly early in July and 7cm stubble was secondly (710.00DM kg/hm2) . The crude protein content of Old World bluestem of three clippings takes on single-peak curve. The content was highest (11.55%) clipping firstly at the middle ten days in July and 7cm stubble treatment, 4cm stubble was secondly (11.31%) ,and treatment clipping.firstly early in July and 1cm stubble was lowest (9.76%) .The ADF and NDF contents of forage were lower clipping firstly early in July and 4cm stubble.